space-saving ideas for small plants
I bought a big bunch of hoya cuttings (32 different species) some months ago - really too many for the space I have when/if they all start growing all over the place. None of them died to save me space - a nice problem to have for sure. All are rooting in clear plastic cups with holes drilled in the bottoms. They are rooting at very different speeds, some (5-7 cups at least) are very well rooted with roots visible all over the cup walls. These are probably ready to be moved out of my humidity container into the open apartment air where they could hopefully grow stems/leaves rather than roots under better (artificial) light but less humidity.
What kinds of ideas do you have to save space for relatively small pots?
I am thinking of two:
The one I like less is to repot several different hoyas into larger communal pots together. That will definitely save shelf space, but I am worried that stronger plants' roots will dominate slower growing hoyas, and also that untangling those roots later if/when I decide to separate the plants will be difficult.
The other is to keep species in individual cups, place each cup into another cup of the same size, also with drain holes, place several of these cups into a larger bowl-type container (sort of like pictured in the photo) and cover the gaps with more mix. Advantages are: (1) roots are contained to the same species, so no need to untangle and no domination by stronger root systems, (2) root development can be examined by lifting the inner cup then placing it back into the outer cup, (3) water easier as if it was one container, (3) save space, (4) save time if need to move one container rather than several, e.g. to the sink or shower or whatever, (5) easier to group plants into different groups for whatever reasons (size, cultural preferences etc.) - just swap the inner cups around.
My mix is very chunky, so over-watering these communal pots should not be a problem, I do not think. I think it WOULD be a concern with more water-retentive soils.
Any thoughts? Any better/other ideas? How do you save space while still growing many plants?